In general, an automatic transmission for a vehicle is controlled using a hydraulic pressure for driving a transmission solenoid valve after a target gear ratio is set based on a transmission map table. The transmission map table is set by a transmission control unit (TCU) according to various kinds of detecting conditions, such as oil temperature, coolant temperature, air temperature, a quantity of air, etc., as well as a driving speed and an opening rate of a throttle valve. Gear shift is performed through transmission control by a plurality of transmission operating elements.
The automatic transmission includes a release element which is released in an operating state and an engagement element which is engaged in an operation releasing state, as the gear shift is executed into the target gear ratio. The release and engagement operations are performed through the control of hydraulic pressure supplied to each element.
When the gear shift is performed in an automatic transmission in which the engagement-side element is pressed before the release-side element is released, an interlock phenomenon may occur due to accumulation of the hydraulic pressure on each operating element. Then, the operating elements of the automatic transmission are temporarily locked. When the interlock phenomenon occurs, a shock is generated, thus degrading the shift and ride qualities. In addition, power may not be transmitted from the transmission to a wheel in a moment.
Therefore, there exists a need to prevent the interlock phenomenon from occurring since the interlock phenomenon occurs due to a transmission control error of an automatic transmission.
The description provided above as a related art of the present disclosure is just for helping in understanding the background of the present disclosure and should not be construed as being included in the related art known by those skilled in the art.